/**********************************************************************************************
 * Arduino PID Library - Version 1.1.1
 * by Brett Beauregard <br3ttb@gmail.com> brettbeauregard.com
 *
 * This Library is licensed under a GPLv3 License
 **********************************************************************************************/
#ifndef PID_v1_h
#define PID_v1_h
#define LIBRARY_VERSION	1.1.1

class PID
{
public:
	//Constants used in some of the functions below
#define AUTOMATIC	1
#define MANUAL	0
#define DIRECT_PID  0
#define REVERSE  1

	//commonly used functions **************************************************************************
	PID(double*, double*, double*, double, double, double, int);  // constructor.  links the PID to the Input, Output, and setpoint.  Initial tuning parameters are also set here

	void SetMode(int Mode);               // * sets PID to either Manual (0) or Auto (non-0)

	bool Compute();                       // * performs the PID calculation.  it should be
	//   called every time loop() cycles. ON/OFF and
	//   calculation frequency can be set using SetMode
	//   SetSampleTime respectively

	void SetOutputLimits(double, double); //clamps the output to a specific range. 0-255 by default, but
	//it's likely the user will want to change this depending on
	//the application

	//available but not commonly used functions ********************************************************
	void SetTunings(double, double, double);      // * While most users will set the tunings once in the
	//   constructor, this function gives the user the option
	//   of changing tunings during runtime for Adaptive control
	void SetControllerDirection(int);	  // * Sets the Direction, or "Action" of the controller. DIRECT
	//   means the output will increase when error is positive. REVERSE
	//   means the opposite.  it's very unlikely that this will be needed
	//   once it is set in the constructor.
	void SetSampleTime(int);              // * sets the frequency, in Milliseconds, with which
	//   the PID calculation is performed.  default is 100

	//Display functions ****************************************************************
	double GetKp();						  // These functions query the pid for interal values.
	double GetKi();						  //  they were created mainly for the pid front-end,
	double GetKd();						  // where it's important to know what is actually
	int GetMode();						  //  inside the PID.
	int GetDirection();					  //

private:
	void Initialize();

	double dispKp;				// * we'll hold on to the tuning parameters in user-entered
	double dispKi;				//   format for display purposes
	double dispKd;				//

	double kp;                  // * (P)roportional Tuning Parameter
	double ki;                  // * (I)ntegral Tuning Parameter
	double kd;                  // * (D)erivative Tuning Parameter

	int controllerDirection;

	double *myInput;              // * Pointers to the Input, Output, and Setpoint variables
	double *myOutput;             //   This creates a hard link between the variables and the
	double *mySetpoint;           //   PID, freeing the user from having to constantly tell us
	//   what these values are.  with pointers we'll just know.

	unsigned long lastTime;
	double ITerm, lastInput;

	unsigned long SampleTime;
	double outMin, outMax;
	bool inAuto;
};
#endif
